The present invention relates generally to wireless communications, and more particularly to the lawful intercept of wireless communications.
Court authorized access to telephone communications and call-identifying information is one of the most crucial tools for effective law enforcement. The introduction of new digitally based technologies, transmission modes, services, and features have made it increasingly difficult for law enforcement to conduct court authorized electronic surveillance. In particular, it is now difficult to tap wireless communications because communication channels are dynamically provisioned wireless channels, such that there is no static line to tap, and furthermore because subscribers frequently move from one wireless service provider to another.
In October of 1994, at the request of the nation""s law enforcement community, Congress took action to protect public safety and national security by enacting the Communications Assistance for Law Enforcement Act (CALEA). CALEA sets forth the interception assistance capability requirements that telecommunications carriers need to meet and maintain within their networks to assist law enforcement in conducting electronic surveillance. These requirements apply to the intercept of wireless communications. Referring to FIG. 1, there is illustrated in simplified form an overview of a wireless network 1. Network 1 includes a number of cells 2 each with an antennae 3 connected to a mobile switching center (MSC) 4. MSC 4 is in turn connected to the SS7 network 5 and the public switched telephone network 6. Cells 2 each serve a plurality of wireless subscribers 7.
In order to meet the requirements of law enforcement to intercept wireless communications, the telecommunications industry has defined an interface specification between a Telecommunication Service Provider (TSP) and a Law Enforcement Agency (LEA), called the J-STD-025. The J-STD-025, xe2x80x9cLawfully Authorized Electronic Surveillancexe2x80x9d, is a joint standard by the Telecommunications Industry Association (TIA) Committee TR45.2 and the Alliance for Telecommunications Industry Solutions (ATIS) Committee T1-Telecommunications. Compliance to J-STD-025 is seen by the telecommunications industry as xe2x80x9csafe harborxe2x80x9d under Section 107 of the CALEA, Public Law 103-414.
J-STD-025 views the intercept function as five broad categories: access, delivery, collection, service provider administration, and law enforcement administration. The relationships between these functional categories are shown in FIG. 2. As illustrated in FIG. 2, the Service Provider Administration Function 10 is responsible for controlling the TSP access and delivery functions. The Law Enforcement Administration (LEA) Function 12 is responsible for controlling the LEA collection functions. The Access Function 14, consisting of one or more Intercept Access Points (IAPs), isolates an intercept subject""s communications or call-identifying information unobtrusively. The Access Function 14 provides access to wireless communications traversing a wireless network such as that illustrated in FIG. 1. The Delivery Function 16 is responsible for accepting information from one or more Access Functions 14 and delivering intercepted communications to one or more Collection Functions 18. The Delivery Function 16 delivers information over two distinct types of channels: Call Content Channels (CCCs) and Call Data Channels (CDCs). The CCCs are generally used to transport call content, such as voice or data communications. The CDCs are generally used to transport messages which report call-identifying information, such as calling party identities and called party identities. The Collection Function 18 is responsible for collecting and analyzing intercepted communications and call-identifying information. The Collection Function 18 is the responsibility of the LEA.
According to one embodiment of the invention, there is provided a system for intercept of wireless communications which includes a home location register (HLR) including one or more surveillance flags associated with a subscriber served by the HLR, and wherein the flag(s) indicate one or more aspects of the subscriber""s wireless communications are to be monitored. A Gateway Delivery Function module provisions the flags in the HLR, and receives call associated data for a subscriber under surveillance. A Delivery Function module, provisioned by the Gateway Delivery Function module, receives call associated data for the surveilled subscriber from the Gateway Deliver Function module and call content for the respective call. The Delivery Function module delivers the call content and call associated data to a desired destination. These and further aspects of the embodiments of the invention are described and claimed below.